竹类是木本为主的克隆植物，具有生长快、繁殖率高、适应性强等入侵植物生物学特性，因而竹林扩张被广泛报道。中国拥有世界最丰富的竹资源，认识竹林扩张的生态效应及驱动机制是制定竹林管理策略的重要依据。凋落物分解是养分循环的关键一环，影响生态系统生产力。竹林扩张伴随微环境及凋落物质量一系列变化，然而其对分解的影响机制尚不清楚。分解驱动的养分循环是否扮演竹林扩张的助推器有待解答；由于生理整合机制的存在，竹林扩张是否仍遵循入侵植物对分解影响的理论范式也未可知；气候是分解的重要驱动力，气候变化将缓解还是加速上述养分循环驱动的竹林扩张亟待解释。土壤生物在上述过程中又扮演怎样的角色？拟沿气候样带尺度（9个站年均温15.6~24.5℃）开展局地（竹林、竹阔界面、阔叶林）凋落物互置分解实验，结合土壤生物功能群和凋落物质量处理、13C/15N双标记凋落物跟踪碳、氮路径等手段观测分解速率及养分释放，回答上述命题。

Bamboo, mainly composed of woody species, is a kind of clonal plant. It has typical biological properties of invasive plants, including fast growth, high reproduction rate and adaptability. Therefore, bamboo expansion has been widely reported across the world. China has the most significant bamboo resources in the world, thus it is critical to understand the driving mechanism and ecological consequences of bamboo expansion, in order to propose reasonable and effective management strategies for bamboo forests. Plant litter decomposition is one of the cogs in the gear of ecosystem functioning. The decomposition process allows recycling of carbon and nutrients from dead organic matter, fuelling new primary production. Bamboo expansion is a process of changes in vegetation composition, microclimate and litter quality, while its effects on litter decomposition are still unclear. Whether the litter decomposition-driven nutrient cycling plays a facilitator of bamboo expansion is still unanswered. Due to the existence of physiological integration of bamboos, it is unknown if the effects of bamboo expansion on decomposition still follow the paradigm of general invasive species do to the decomposition. Will it increase the nutrient availability by accelerating decomposition in order to facilitate expansion, or decrease the nutrient availability by slowing down decomposition in order to inhibit the regeneration of the invaded community? Climate is one of the most important drivers of decomposition, but will climate warming alleviate the nutrient limitation to the invaded community caused by bamboo expansion then slow the expansion speed as a consequence? Additionally, the roles that different soil biota communities play in all abovementioned processes are unknown. We propose to choose nine locations across a national scale along a climatic gradient (15.6~24.5℃). In each location, sites with different bamboo density will be established in order to conduct both in situ and reciprocal decomposition experiment. Soil biota community will be manipulated by employing three mesh sizes litter bags or microcosms, enable us to distinguish three increasingly complete decomposer communities (small, medium-sized and complete). Dual-labelled (13C/15N) litter decomposition will be conducted to trace litter-derived C and N in soils. By investigating mass loss and nutrient release of all our decomposition experiments, we intend to answer above-developed questions.